Timed fuel injection system

ABSTRACT

A timed fuel injection system for an internal combustion engine has a fluidic amplifier for each cylinder. The amplifier acts to divert fuel back to a reservoir when the cylinder&#39;&#39;s intake valve or equivalent is closed and to switch fuel to the injector when the intake valve is open. The amplifier diverts fuel when the vacuum within one cylinder&#39;&#39;s intake manifold is exceeded by the average vacuum of all cylinders and switches fuel when the intake vacuum of the one cylinder exceeds the average vacuum of all cylinders.

United States Patent [1 1 Martin TIMED FUEL INJECTION SYSTEM Norman W. Martin, 6008 8 Maine Road, Plattsburgh Air Force Base, N.Y. 12903 Filed: Nov. 17, 1971 Appl. N0.: 199,609

Inventor:

US. Cl. 123/139 AW, 123/119 R, l23/DIG. l0,

261/DIG. 69

Int. Cl. F02m 39/00 Field of Search 123/DIG. 10, 139 AW, 123/119 R, 103 R; 261/DIG. 69 X [5 6] References Cited UNITED STATES PATENTS 2/1 959 Goodridge et al. 123/139 AW Nardi 123/DlG. l0 Timpner l23/DlG. 10

[ June 26, 1973 3,669,423 6/1972 Hohsho et a1 l23/D1G. 10

Primary Examiner-Carlton R. Croyle Assistant Examiner-Richard Sher Att0rney--Lucas Albright, William B. Mason et al.

[5 7 ABSTRACT A timed fuel injection system for an internal combustion engine has a fluidic amplifier for each cylinder. The amplifier acts to divert fuel back to a reservoir when the cylinders intake valve or equivalent is closed and to switch fuel to the injector when the intake valve is open. The amplifier diverts fuel when the vacuum within one cylinders intake manifold is exceeded by the average vacuum of all cylinders and switches fuel when the intake vacuum of the one cylinder exceeds the average vacuum of all cylinders.

6 Claims, 4 Drawing Figures PAIENIED .um 26 I973 SHEET 2 BF 2 720ATDC OYLINDER I CYLINDER 2 CYLINDER 3 CYLINDER 4 FIG. 4

TIMED FUEL INJECTION SYSTEM Conventional carburetors mix air with fuel by means of a pressure drop across a venturi. This arrangement has the disadvantage that a venturi dimensioned small enough to meter fuel at low throttle, is too small for optimum performance at high throttle. The present invention has as its prime object to provide a timed fuel injection which is highly efficient with respect to economy, power production and hydrocarbon emission both at low and high throttle. A further advantage of the present invention is that the pressure of the airfuel mixture is actually increased above atmospheric at the engine cylinder to supercharge same and the mixture is more even than is realized in conventinal carburetion.

It is therefore an object of the present invention to provide a timed fuel injection system for an engine which has no moving mechanical parts, but which uses a switch in the form of an amplifier responsive to the vacuum changes produced by the intake valve means of the engine.

It is another object to control the fluidic switch by using the differences between the vacuum developed in any one cylinder and the average vacuum developed by all cylinders.

These and other objects will be apparent from the following description and appended drawings in which:

FIG. 1 is a schematic view of the fuel injection system;

FIG. 2 is a section of a fluidic amplifier used in the FIG. 1 system; and

FIG. 3 is a section of the vacuum averaging collector showing baffles.

FIG. 4 is a graph of the vacuum values of each cylinder in FIG. 1.

In FIG. 1, a high capacity pump 1 receives fuel at its intake side from reservoir 3 and pressures fuel at a pressure, P3 to an inlet 5a of a fuel pressure regulator 5. The pressure-regulator has a first outlet 5b in direct return communication with reservoir 3 and a second outlet 5c in communication with a manifold 7, through conduit 7a. The engine, shown in part, represents an Otto 4 cycle engine by way of example in which each combustion chamber 11 of each cylinder has an intake valve 13 and a piston 15. The pistons and valves are identical for each cylinder and are shown in section with only one set of numbers to avoid repetition; the other engine parts are omitted, bieng conventional and forming no part of the invention.

Each intake valve 13 is located at the bottom of an intake track 17 and each track has the usual butterfly valve 19 to admit air responsive to acceleration or throttle increase.

During operation each track 17 develops a relatively high vacuum (or low pressure drop) when valve 13 opens. The pressure above valve 19 is essentially constant and about the same as atmospheric pressure. The interior of each track 17 has a conduit 21 located below butterfly valve 19 leading to vacuum averaging collector 23, which is an enclosed chamber with baffles 230, shown in FIG. 3, so that the average vacuum P, of all tracks 17 is developed at any time within the collector 23.

The collector 23 has a further conduit 25 in communication with one side of a vacuum diaphram 27 and the other side of the diaphram is connected by a crank 29 to the fuel pressure regulation valve 5. The average vacuum, P acting on diaphram 27 moves the valve in regulator 5 so that a proportional amount of fuel is diverted back to reservoir 3, lowering the pressure P of fuel from pump 1, to P The pressure, P, controls the ultimate richness of fuel being injected in the engine.

Fuel at pressure P, is communicated through conduit 7a to manifold 7 and then to another conduit 7b, associated with each track 17. The conduits 7b each lead to their respective two-phase bistable fluidic amplifier 31 shown in FIG. 2. The amplifier 31 functions as a fluidic switch with no moving parts. Thus, fuel under pressure, P; enters amplifier 31 and either is returned to reservoir 3 via conduit 31a and manifold 8, or is injected in its respective track 17 via injector 31b. A first passage 31c leads from the amplifier to the interior of track 17 below butterfly valve 19 to sense the intake vacuum I, of its respective track 17. A second passageway 31d on the opposite side of amplifier 31 leads to the collector 23 which develops an average vacuum of P It will be apparent that fuel enters amplifier 31 at pressure P, and is diverted back to reservoir 3 when the average vacuum P of all intake tracks exceeds that vacuum, P of any individual track 17, and this condition prevails so long as valve 13 is closed. When the intake valve 13 of any track 17 is open, or partly open, the vacuum P, of that track exceeds P, which is always the average vacuum of all tracks. At this time, fuel is switched from conduit 31a to injector 31b and is drawn into the chamber 11 during intake prior to compression.

In FIG. 4, the vacuum values of each cylinder are shown plotted with each cylinders position being along vertical line X X when the conditions of the cylinders are as shown in FIG. 1. At that instant, cylinder 4 has a relatively high vacuum value because it is about at the peak of its intake stroke. Cylinders 1, 2 and 3 all have substantially atmospheric pressure at the instant of line X X shown in FIG. 1. The power stroke of each cylinder begins at 0 along the horizontal line and near 360 ATDC, the intake stroke begins so that the vacuum P, for each cylinder increases to peak at about 30 inches Hg.

Thus, the system described constitutes timed fuel injection, that is, fuel is injected only when the pressure changes in the intake track due to the engine cycling when in operation and this timing is accomplished with out moving parts and realizes near optimum fuel-air mixing. Thus, low hydrocarbon emission takes place and high cycle efficiency, i.e., good gas mileage and power potential, is realized at low unit expense and maintenance.

The timed injection systems described herein can be used in all types of internal combustion engines, Wankel, Diesel, Otto, and both two and four stroke engines. since these engines all operate to periodically develop a relatively high vacuum upon each cylinders intake which exceeds the average vacuum of all cylinders. The term intake valve" used herein means the intake which can be a track without an actual valve such as found in an Otto engine for instance.

In the present invention, the use of a fluidic amplifier involves no moving parts to effect the switch of pressured fuel from reservoir to cylinder and vice-versa. It should be noted that switching time is not a limiting factor because this time is linearly proportional to a fluidic amplifiers critical dimensions. Thus, reducing these dimensions makes the switch even more precise 3 and precise switching at, say, 10,000 rpm is easily accomplished.

In the amplifier 31 shown in FIG. 2, the amplifier is merely representative with the various passages and conduits not drawn to scale. Likewise, the vacuum averaging chamber 23 of FIG. 3 and the baffle arrangement of the chamber are for illustrative purposes only and other structures are operative. In this connection, a relatively small collector having multiple inlets 31c (in this case 8 inlets, one for each cylinder) will suffice and the more inlets, the less baffling needed. In short,

the collector 31 need only be baffled enough so that output average vacuum through conduit 25 be unfluctuating.

The vacuum P, for each cylinder varies during engine cycle as shown in FIG. 4, the vacuum P, being about atmospheric (or O in the graph) during power, exhaust and compression. During intake, however, P fluctuates before and after peak in the track to exceed the average vacuum P, as stated above. Using one baffled vacuum averaging collector for each intake track, P, can be determined during the cycle'for each cylinder or track because of the fluctuation of P during the intake portion of each cycle with the peak of P being realized at the instant the cylinders intake valve is completely open. Because of the baffles and since the engine is cycling at hundreds or thousands of times each minute, there will always be a pressure difference between P, and P With single cylinder engines, or when using an averaging collector for each cylinder, the collector should be largerand more baffled than is the case with multicylinder engines.

What is claimed is:

1. A timed fuel injection system for an internal combustion engine comprising at least one cylinder and engine track means associated withthe cylinder intake means at one end of said track means, said system including a high capacity fuel pump in communication with a reservoir and a pressure regulator, said pressure regulator having a first outlet in communication with a fluidic amplifier for said track means, said amplifier being positioned to alternatively inject fuel in said track means and by-pass fuel to said reservoir, said amplifier being connected to a first passage which leads to the interior of said track means for communicating the prevailing intake vacuum and a second passage leading to a vacuum averaging collector, said collector being in communication with the interior of the track means, whereby said amplifier functions to divert pressured fuel to the reservoir when the pressure in the track means is relatively high and the vacuum in the second passage exceeds that in the first passage, and said amplifier switches pressured fuel to the interior of said track means when the pressure in said intake is relatively low and the vacuum in the first passage exceeds that in the second passage.

2. The system of claim 1, wherein said engine has a plurality of cylinders and each cylinder is associated with a respective track of said track means.

3. The system of claim 1, wherein said vacuum averaging collector is connected to one side of a diaphram and said diaphram is operatively associated with a valve regulator to proportion the amount of fuel returned directly to the reservoir through said first outlet.

4. The system of claim 1, wherein said track means includes butterfly valve means and a conduit leads from said track means below said butterfly valve means to the vacuum averaging collector.

5. The system of claim 4, wherein the first passageway also leads in said track means below the butterfly valve.

6. The system of claim 1, wherein said vacuum averaging collector comprises an enclosure which is baffled internally.

* III 

1. A timed fuel injection system for an internal combustion engine comprising at least one cylinder and engine track means associated with the cylinder intake means at one end of said track means, said system including a high capacity fuel pump in communication with a reservoir and a pressure regulator, said pressure regulator having a first outlet in communication with a fluidic amplifier for said track means, said amplifier being positioned to alternatively inject fuel in said track means and by-pass fuel to said reservoir, said amplifier being connected to a first passage which leads to the interior of said track means for communicating the prevailing intake vacuum and a second passage leading to a vacuum averaging collector, said collector being in communication with the interior of the track means, whereby said amplifier functions to divert pressured fuel to the reservoir when the pressure in the track means is relatively high and the vacuum in the second passage exceeds that in the first passage, and said amplifier switches pressured fuel to the interior of said track means when the pressure in said intake is relatively low and the vacuum in the first passage exceeds that in the second passage.
 2. The system of claim 1, wherein said engine has a plurality of cylinders and each cylinder is associated with a respective track of said track means.
 3. The system of claim 1, wherein said vacuum averaging collector is connected to one side of a diaphram and said diaphram is operatively associated with a valve regulator to proportion the amount of fuel returned directly to the reservoir through said first outlet.
 4. The system of claim 1, wherein said track means includes butterfly valve means and a conduit leads from said track means below said butterfly valve means to the vacuum averaging collector.
 5. The system of claim 4, wherein the first passageway also leads in said track means below the butterfly valve.
 6. The system of claim 1, wherein said vacuum averaging collector comprises an enclosure which is baffled internally. 